Rút gọn:
a. \(\sqrt{2a}\) \(\times\) \(\sqrt{18a}\) (a \(\ge\)0)
b. \(\sqrt{3a\times27ab^2}\)
c. 2y2 \(\times\) \(\sqrt{\dfrac{x^4}{4y^2}}\) (y < 0)
d. \(\dfrac{y}{x}\) \(\times\) \(\sqrt{\dfrac{x^2}{y^4}}\) (x > 0 ; y \(\ne\)0)
e. \(\sqrt{\dfrac{9a^2}{16}}\)
f. \(\sqrt{10.16a^2}\) (a < 0)
g. \(\sqrt{a^4}\left(3-a\right)^2\) (a \(\ge\) 3)
h. \(\sqrt{\dfrac{2a^2b^4}{98}}\)